Psychology- Research methods in cognitive psychology

What are the strengths of a lab experiment?

- They use standardised procedures so they're easier to replicate

- cause-and-effect = good internal validity

- Quantity increases validity

What is a lab experiment?

Studies which take place in a controlled environment

What are the weaknesses of a lab experiment?

- It isn't a natural environment so it lacks ecological validity

- Tasks are not realistic = lacks mundane realism

Unrealistic so creates demand characteristics

What is a field experiment?

Studies that take place in a real life natural setting

What are the strengths of a field experiment?

- Conducted in a real world setting which creates ecological validity

- Cause an effect as easier to establish

- Demand characteristics are reduced

What are the weaknesses of a field experiment?

- Hard to control the environment it is not as easy to replicate as a lab experiment

- Could lack mundane realism

How do you do this?

- Making variables precise, specific and measurable

- This means deciding exactly how you are going to manipulate the independent variable and exactly how the dependent variable will be recorded

How would you operationalise the following hypothesis?

- Students are more alert in the morning

Independent variable - what time, 7 am to 7 pm?

Dependent variable - how fast they react to things - ruler task (cm)

How would you operationalise the following hypothesis?

- Caffeine will have an effect on the time completing a puzzle

Independent variable - amount of caffeine (500 mL, same coffee) caffeine or no caffeine

Dependent variable - time completing a puzzle (minutes /seconds)

What is an independent variable?

The variable that is manipulated or changed by the researcher

What is a dependent variable?

The variable that is recorded or measured by the researcher

What is a research aim?

- A general statement of what the researcher intends to investigate

- The purpose of the study

- Concise to the point statement that directs the overall ambition of the study

- Typically begins with "to investigate..."

What is a hypothesis?

- A prediction of what is likely to happen in the investigation based on previous knowledge , research or theory

- a clear, precise and testable statement of the relationship between the variables to be investigated

What is the directional hypothesis?

The direction of the results can be predicted(there must be previous research to indicate this)

What is a nondirectional hypothesis?

A change of difference is predicted, but not the direction it will go in (conflicting theories or lack of relevant evidence)

What is a null hypothesis?

Predict no difference or relationship will be found or that any difference is due to chance factors

What is an extraneous variable?

In an experiment, any variable other than the independent variable that might potentially affect the dependent variable e.g. noise, temperature, age, sleep, time of day

What is a confounding variable?

A special class where the variable changes systematically with the independent variable. If any extraneous variables impact results, they become confounding variables.

What is a situational variable?

These must affect a whole group or test in order for it to be an issue

What is a participant variable?

Participants may bring different characteristics to an experiment that could affect the dependent variable e.g. gender comment intelligence, level of experience

What is a demand characteristic?

When participants alter their behaviour to meet the perceived demand of experiment, this can reduce validity and make the experiment untruthful

What are experiment effects?

The presence of researcher affects performance for example a teacher this can reduce the validity and make the experiment untruthful

What is an experimental design?

The different ways in which the testing of participants can be organised in relation to the experimental conditions

What is the independent groups design?

When participants are divided into groups and are only involved in one of the experimental conditions of the experiment

What is matched pairs design?

When different participants are assigned to each condition of the experiment, but they are matched on characteristics important to the study

What is repeated measures design?

When all participants take part in all conditions of the experiment

What is a control group?

A group of participants who do not experience the experiment situation but act as a baseline against which to judge any change

What are the strengths and weaknesses of an independent group design?

Strengths -

- Avoids affects such as fatigue, boredom and practice effects that can be a problem

when repeating a task - increased validity

- reduces likelihood of demand characteristics - increased validity

- Easier than matched pairs design

Weaknesses -

- Differences between groups may be due to individual differences - participant variables - decrease in validity

- More participants needed

What are the strengths and weaknesses of repeated measures design?

Strengths

- There are no participant variables - increased validity

- Requires less participants

Weaknesses

- Can introduce order effects for example fatigue and boredom - reduced validity

- Demand characteristics can affect results - reduced internal validity

What are the strengths and weaknesses of matched pairs design?

Strengths

- Fewer participant variables - increased validity

- Avoids order effect - increased validity

- Less likely to get demand characteristics - increase validity

Weaknesses

- Still risk of participant variables - decrease validity

- Matching participants is time consuming

What is counterbalancing?

Alternating the order of the condition in a repeated measures design so that the order effects are minimised

What does it mean to operationalise variables?

To make the variables precise and specific

What are the strengths of the mean?

More sensitive than the median because it makes use of all the values of the data

What are the disadvantages of the mean?

It can be misrepresentative if there is an extreme value

What are the strengths of using the median?

It isn't affected by extreme scores so it can give a representative value

What are the disadvantages of using the median?

It's less sensitive than the mean, as it does not take into account all of the values

What are the strengths of using the mode?

It is useful when the data is in categories

What are the disadvantages of using the mode?

It is not a useful way of describing data when there are several modes

Needs big data sample to give a valid value

What are the two types of measures of dispersion?

Range and standard deviation

What are the strengths and weaknesses of using the range?

Strengths - easy to calculate

Weaknesses - only takes into account the two most extreme values. This makes it unrepresented of the data as a whole.

What is standard deviation?

A value that tells us how far goes move away from the mean

Strengths and weaknesses of standard deviation

Strength - much more precise measure of dispersion than the range as it includes all values within the final calculation

Weaknesses - it can be distorted by single extreme value

What are the five steps to work out the standard deviation?

Step one - out the main

Step two - subtract the mean from each score

Step three - square the deviation score

Step four - add up the squared deviation scores and divide by one less than the total scores in data set

Step five - find the square root of the variance

What is a bar chart?

Used to present data from a categorical variable

What is a histogram?

Used to present the distribution of school by showing the frequency of values in the data set

What is statistical testing?

Provides a way of determining whether hypotheses should be accepted or rejected. In psychology, they tell us whether differences or relationships between variables are statistically significant or have occurred by chance.

When choosing a statistical test, what three factors need to be considered?

1- research method-is it a test of difference(experiment) or a test of correlation(relationship)?

2- results- what is the level of measurement? (nominal/ordinal/interval/ratio?

3-participants- what experimental design was used - independent or repeated measures?

What are the three levels of measurement?

Nominal, ordinal, interval

What is nominal?

Data is put into categories, how many people in each category

Discrete data = one item in one category

What is ordinal measurement?

When data can be put into order, does not have equal intervals between each unit(cannot tell us what the gap is between 1st and 2nd)

What is interval measurement?

Equal intervals (e.g. gap between 2 cm and 4 cm is the same as the gap between 5 cm and 7 cm)

Time, temperature, weight

What stats test should you do if the test for difference is unrelated data and nominal?

Chi squared (X2)

What stats test should you use if it is a test of difference of unrelated data and ordinal?

Mann Whitney (U)

What stats test should you use if it is a test of difference of related data and ordinary?

Wilcoxon (t)

What stats test should you use if it is a test of correlation and ordinal?

Spearman's tho (r)

What is three factors are needed to run a Mann-Whitney U test?

1. Test of difference.

2. Ordinal data.

3. Independent groups design.

Ppl